Development and microstructural–mechanical evaluation of sustainable high-entropy bronze from electronic waste and foundry scrap recycling

Abstract

The escalating generation of electronic waste (e-waste) presents both a critical environmental challenge and an opportunity for sustainable metal recovery. This study investigates the synthesis of high-entropy bronze alloys (HEBAs) using metallic fractions extracted from e-waste and cast via the crucible induction melting technique. Two multi-component CuSnPbZnAlNiCrMnSi-HEBAs compositions were developed and subjected to comprehensive microstructural and mechanical characterization. Optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) revealed a primarily homogeneous matrix with a dominant CuSnMn-rich solid solution and intermetallic phase precipitates such as NiCuMnAl along dendritic arms. X-ray diffraction (XRD) analysis confirmed a face-centered cubic (FCC) dominant phase, accompanied by secondary body-centered cubic (BCC) and complex intermetallic structures, indicative of multiphase stability and solid solution formation. Microhardness values ranged from 218 HV to 395.8 HV, attributed to solid solution strengthening and dispersion of secondary hardening phases. The results validate the feasibility of producing structurally sound and mechanically robust HEBAs from recycled e-waste. This work demonstrates a viable approach to alloy upcycling and supports circular economy principles through the development of advanced materials from complex secondary feedstocks. .